The present invention relates generally to electric power drills, particularly hand-held electric power drills. More particularly the present invention relates to devices for facilitating the use of hand-held electric power drills, and still more particularly to devices which use mechanical advantage to facilitate the use of hand-held electric power drills
Though power drills apply the force to turn the drill bit, the force required to push the drill bit along its longitudinal direction into the object to be drilled is provided by the user. Application of the required forces can be ergonomically difficult, straining and tiring, and result in lower productivity, higher stress and higher cost.
Electricians and plumbers in the construction trades regularly bore holes in studs and joists in order to slide wires and pipes through them. The holes range in size from xc2xd inch to 4 inches, with xc2xe inch and 1 inch most common. A considerable amount of pressure must be consistently applied to the drill motor to bore the hole, and often dozens of holes must be bored during a short period. By the time the actual work of plumbing or wiring can begin, the tradesman is tired from boring labor.
Self-augering drill bits which utilize a center mounted screw device to pull the cutting portion of the drill bit through the material to be bored are available but expensive and difficult or impossible to sharpen. These bits become useless once they strike a nail or screw, breaking off and dulling the cutting tips, requiring their replacement, at high cost. Even self-augering drill bits require a final xe2x80x98pushxe2x80x99 to complete drilling. This push results in a lunging forward as the drill bit breaks through. The device of the present invention increases pressure applied as well as increases control during drilling, eliminating the uncontrolled lunging effect.
Furthermore, holes often need to be drilled in difficult to reach spots, such as overhead, making the ergonomics of applying pressure to the drill even more physically awkward, time and energy consuming, and therefore extremely tiring. The force required to push the drill bit through the bore varies with the size of the hole diameter, type and design of the drill bit being used, blade sharpness, drill speed and material being drilled. In all cases, a consistent pressure applied to the drill bit is desirable. The pressure required to be applied to the drill bit throughout the drilling operation varies widely from no pressure applied, to as much as 50 pounds per square inch directed to the drill bit, applied to the longitudinal axis of the drill bit.
Through the years, various techniques of applying force to a portable drill have been developed, specific to the material and object being drilled, location, ergonomics, etc. Several devices have been patented, utilizing a lever to create force. The methods of creating the force and methods of applying the force to the drill motor significantly differ from those of the present invention.
For instance, U.S. Pat. No. 4,168,926, to Rudolph Belcourt, Sep. 25, 1979, requires access to wrap around the object to be drilled, intended for use on pipes. It is not applicable to the object of this invention because of the requirement of clear access to the object being drilled, cumbersome nature of the chains, and longer time required to set up and complete each drilling operation.
U.S. Pat. No. 5,863,158, to George T. Foshee Jr., Jan. 26, 1999, the user must drill a hole to drill a hole, for attaching a bolt and chain to pull against. Though this device could be used in some applications, it is not practical or advisable to drill two holes in order to drill one.
U.S. Pat. No. 5,445,480, to Denys J. Merriman, Aug. 29, 1995, is appropriate for drilling steel beams, where the material being drilled is comparatively thinner than the materials which are intended to be drilled by the present invention, where the hole must be completed with a limited degree of angular movement of the drill bit. This angular movement would be inappropriate for drilling thicker wood, especially multiple layers or beams. The system of pulling from the opposite side of the material being drilled is unable to be used for drilling into interior corners, and studs and joists where accessibility is limited.
U.S. Pat. No. 4,136,579, to Merle W. Robinson, Jan. 30, 1979, (FIG. 9 shows the Robinson device and is provided to clarify the differences between the present invention and this prior art.) Leverage pressure is created by pushing off an adjacent stud or joist using a rolling bearing 32, and linking the lever through a fixed pivot point 22 on the unit housing. The rolling contact point 32 is intended to roll as it is pushed off the adjacent stud. Its use is optimized for specific 16 inch on center stud and joist spacing. It has minimal provision for adjustment of link 18 to allow for variations in stud and joist spacing and requires an external tool to adjust, which is difficult and time consuming. Because of its limited application, difficulty and limits of adjustment, this prior art accessory did not become commercially accepted.
A leverage accessory for hand-held power drills comprises a lever having a handle at one end and a sharp pointed tip at the other end for plunging into sheathing attached to the stud or joist being drilled. An instantly repositionable, non-slip contact section connects the lever to the drill body to apply force. The device can be adapted to existing drill motors, and may be made integral to drill motor/lever units.
An object of the present invention is to provide for application of mechanical advantage to a hand-held power drill to allow the operator to drill holes in studs and joists in a more efficient and ergonomically satisfactory manner.
Therefore, it is an object of the present invention to provide an apparatus for applying mechanical advantage to the longitudinal force applied to a drill.
It is another object of the present invention to stabilize the position of the drill motor during the drilling process.
More particularly, it is an object of the present invention to provide a means for attachment of a lever to a drill motor to assist in providing a longitudinal force and stabilization of a drill.
Another object of the present invention is to provide flexible adaptability to each new hole boring application without need for complicated adjustment of the tool.
It is also an object of this invention to make said device instant and intuitive for the user, in order to facilitate rapid setup, execution of the drilling operation and removal for repetitive use in the field.
Advantages include improvement of ergonomics, ease of drilling, speed, safety, control and better accessibility to remote locations for drilling in studs and joists.